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Leucocytes
- 2. SPECIFIC LEARNING OBJECTIVES At the end of the class the student must be able to Decribe the normal values functions of leucocytes Explain the RES (Reticulo endothelial system)
- 3. WBC WBC differ from RBC – Hb and nucleus Ratio RBC and WBC – 600:1 Total leucocyte range – 4000 – 11000 / mm3
- 4. CLASSIFICATION WBC Granulocytes Agranulocytes Neutrophil Eosinophil Basophil Monocyte Lymphocyte
- 5. NORMAL VALUES Total count – adults – 4000 – 11,000 cells/cu.mm. - at birth 10,000 – 25,000 cells/cu.mm. Cell Differential Count Absolute count (cells/cu.mm.) Neutrophil 50 – 70% 2000 – 7000 Eosinophil 1 – 4% 50 – 500 Basophil 0 – 1% 10 – 100 Monocyte 2 – 8% 200 – 800 Lymphocyte 20 – 40% 1500 - 4000
- 8. GRANULOCYTES GRANULOPOIESIS – production and maturation of granulocytes SITE OF FORMATION Before birth – mesoderm, liver & spleen After birth – red bone marrow During development – granulocytes lose their capacity to divide and attain specific morphological features – finally develop into functionally competent cells
- 9. STAGES OF GRANULOPOIESIS Haemocytoblast/pluripotent cell/non Committed stem cell Committed stem cell Myeloblast Promyelocyte Myelocyte Metamyelocyte Matured granulocytes
- 10. REGULATION OF GRANULOPOIESIS The following factors stimulate the granulopoiesis The rate of production mainly depends on the concentration of these factors Granulocyte-macrophage colony stimulating factor (GM-CSF) Granulocyte colony stimulating factor (G-CSF) Macrophage colony stimulating factor (M-CSF)
- 11. IL-1 IL-3 IL-6 Tumour necrosis factor Fibroblasts Endothelial cells T-lymphocytes
- 12. FUNCTIONS OF NEUTROPHILLS 1.PHAGOCYTOSIS OF BACTERIA These are the frontline soldiers DIAPEDESIS The circulating cells become marginated The cells come out by squeezing through the pores of the capillary wall and Enters the tissue
- 13. CHEMOTAXIS These are attracted to the site of infection by certain chemicals released from the site of infection OPSONISATION Once the cells reach the site – neutrophills start engulfing the bacteria Complements and antibodies get attached to the bacteria
- 14. These are called opsonins The process is called opsonosation Opsonisation facilitates phagocytosis Ca++ ion is required for this process First the cell membrane of neutrophil becomes invaginated until the bacterium is completely engulfed
- 15. Then, the digestive pouch called phagosome is formed This is merged with a lysozome containing hydrolyzing enzyme and bacterial agents like h2o2, myeloperoxidase, lysozyme, lactoferrin These enzymes kill and digest the bacterium A neutrophil can phagocytize 5-20 bacteria
- 17. 2.phagocytosis of antigen-antibody complexes This prevents the harmful reactions that develop due to antigen-antobody reaction 3.phagocytosis of dead cells, foreign particles like carbon particles, sodium urate crystals In other words – neutrophills act as a scavengers Microphages – phagocitize small particles
- 18. Applied aspects Neutrophilia Physiological Pathological Exercise Pregnancy Parturition Emotional stress Acute pyogenic infections Rheumatic fever Myocardial infarction
- 19. ↓ Neutropenia Physiological Pathological Rare Exposure to cold Typhoid Paratyphoid Aplastic anemia Viral infection -measles
- 21. EOSINOPHILLS These are abundant in the mucosa of GIT, urinary and respiratory tract Their maturation is stimulated by IL-3, IL-5, GM-CSF FUNCTIONS Have role in clot lysis – they produce prefibrinolysin Engulf antigen-antobody complexex – and thereby prevent more release of vasoactive substanced
- 22. It participate in antiallergic role – these contains anti- inflammatory histaminases and aryl-sulfatase – which inactivate histamine and SRS-A They have a role in detoxification of certain foreighn proteins A basic proteins present in eosinophills – destroys larval parasites Eosinophillic cationic proteins (ECP) – act as bactericidal and larvicidal
- 23. Eosinophil Eosinophilia ↓ Eosinopenia Allergic conditions arasitic infestations Skin diseases ACTH therapy Acute pyogenic infec Aplastic anemia
- 24. BASOPHILLS It produces heparin – this helps in prevention of intravascular clotting It also contains histamine SRS-A and eosinophillic chemotactic factor So, it may participate in allergic reactions along with mast cells – like urticaria, rhinitis and anaphylactic shock Participate in lipid metabolism
- 25. Basophil Basophilia ↓ Basophilopenia Chronic myeloid leukemia Polycythemia Rare Aplastic anemia
- 26. AGRANULOCYTES LYMPHOCYTES – produced from bone marrow and lymphoid tissue MONOCYTES – produced from bone marrow and liver
- 27. LYMPHOCYTES B LYMPHOCYTES 20 % Produce antibodies Bone marrow Humoral immunity Bacterial infections T LYMPHOCYTES 80% Produce chemicals called cytokines Thymus Cell mediated Viral infections
- 28. LYMPHOCYTES B LYMPHOCYTES Shorter life span Class II MHC present on membrane Have immunoglobulins Agammaglobulinaemia Multiple myeloma T LYMPHOCYTES Longer life span Absent Absent AIDS Various autoimmune diseases
- 29. Lymphocyte Lymphocytosis ↓ Lymphocytopenia Chronic infections Infectious Mononucleosis Lymphoma Viral infection Immunosuppressive therapy ACTH therapy Hodgkin’s disease Bone marrow failure
- 30. MONOCYTE(BLOOD MACROPHAGES) FUNCTIONS These enters the tissue and form the tissue macrophages and act as scavengers Phagocitize several bacteria Engulf large particulate matter, dead tissue cells and senile cells
- 31. Monocyte along with other macrophages involved in phagocytosis and destruction of necrotic material Participate in humoral and cellular immunity
- 32. Monocyte Monocytosis ↓ Monocytopenia Malaria Kala-azar Monocytic leukemia Rare Bone marrow failure Aplastic anemia
- 33. RETICULOENDOTHELIAL SYSTEM Monocyte macrophage system(MMS) Mononuclear phagocytic system (MPS) Generalised phagocytic system Special group of cells scattered in different parts • Powerful phagocytes • Stained by supravital stains Monocytes – macrophages Liver – Kupffer cells CNS – Microglia Lungs – Alveolar macrophages Skin – Langerhans cells Bone – Osteoclasts Lymph nodes, spleen & bone marrow – Dendritic cells Connective tissue – Histiocytes [Fixed & wandering]
- 34. Functions of RES More powerful phagocytic action than Neutrophil Engulf larger particle Engulf more numbers (100) Survive even after ingestion of bacteria Ingest & destroy RBC & release bilirubin Also destroy dead WBC’s & platelets Ingest & process antigen & present it to Lymphocyte(play a role in Immunity) Produce IL-1-activates T cell CSF-GM-regulates erythropoiesis Initiate development of antibody Activated by lymphokines of T lymphocytes.Migrate to area of inflammation & engulf bacteria Sites of hemopoiesis during fetal life(spleen & liver)